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ML4841CP

P1-P3P4-P6P7-P9P10-P12P13-P15
www.fairchildsemi.com
REV. 1.0.3 6/13/01
Features
• Internally synchronized PFC and PWM in one IC
• Low total harmonic distortion
• Reduces ripple current in the storage capacitor between
the PFC and PWM sections
• Average current, continuous mode, boost type, leading
edge PFC
• High efficiency trailing edge PWM can be configured for
current mode or voltage mode operation
• Average line voltage compensation with brown-out
control
• PFC overvoltage comparator eliminates output
“runaway” due to load removal
• Current fed multiplier for improved noise immunity
• Overvoltage protection, UVLO, and soft start
General Description
The ML4841 is a controller for power factor corrected,
switched mode power supplies. Power Factor Correction
(PFC) allows the use of smaller, lower cost bulk capacitors,
reduces power line loading and stress on the switching FETs,
and results in a power supply that fully complies with
IEC1000-2-3 specifications. The ML4841 includes circuits
for the implementation of a leading edge, average current,
“boost” type power factor correction, and a trailing edge,
pulse width modulator (PWM).
The PFC frequency of the ML4841 is automatically set at
half that of the PWM frequency generated by the internal
oscillator. This technique allows the user to design with
smaller output components while maintaining the optimum
operating frequency for the PFC. An over-voltage compara-
tor shuts down the PFC section in the event of a sudden
decrease in load. The PFC section also includes peak current
limiting and input voltage brown-out protection.
Block Diagram
15
VEAO
IEAO
V
FB
I
AC
V
RMS
I
SENSE
RAMP 1
OSCILLATOR
OVP
PFC I
LIMIT
UVLO
V
REF
PULSE WIDTH MODULATOR
POWER FACTOR CORRECTOR
2.5V
+
-
-
+
16
2
4
3
7.5V
REFERENCE
14
V
CC
13
V
CCZ
VEA
8
-
+
IEA
1
+
-
+
-
PFC OUT
12
S
R
Q
Q
S
R
Q
Q
2.7V
-1V
RAMP 2
9
PWM OUT
11
S
R
Q
Q
V
DC
6
SS
5
R
T
C
T
7
V
CC
DUTY CYCLE
LIMIT
+
-
1V
-
+
2.5V
V
FB
-
+
8V
8V
V
IN
OK
GAIN
MODULATOR
V
CCZ
÷2
3.5kΩ
3.5kΩ
1.25V
50µA
-
+
13.5V
DC I
LIMIT
8V
ML4841
Variable Feedforward PFC/PWM Controller Combo
ML4841 PRODUCT SPECIFICATION
2 REV. 1.0.3 6/13/01
Pin Configuration
Pin Description
PIN NAME FUNCTION
1 IEAO PFC transconductance current error amplifier output
2I
AC
PFC gain control reference input
3I
SENSE
Current sense input to the PFC current limit comparator
4V
RMS
Input for PFC RMS line voltage compensation
5SSConnection point for the PWM soft start capacitor
6V
DC
PWM voltage feedback input
7R
T
C
T
Connection for oscillator frequency setting components
8 RAMP 1 PFC ramp input
9 RAMP 2 PWM ramp current sense input
10 GND Ground
11 PWM OUT PWM driver output
12 PFC OUT PFC driver output
13 V
CC
Positive supply (connected to an internal shunt regulator).
14 V
REF
Buffered output for the internal 7.5V reference
15 V
FB
PFC transconductance voltage error amplifier input
16 VEAO PFC transconductance voltage error amplifier output
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
IEAO
I
AC
I
SENSE
V
RMS
SS
V
DC
R
T
/C
T
RAMP 1
VEAO
V
FB
V
REF
V
CC
PFC OUT
PWM OUT
GND
RAMP 2
TOP VIEW
ML4841
16-Pin PDIP (P16)
PRODUCT SPECIFICATION ML4841
REV. 1.0.3 6/13/01 3
Absolute Maximum Ratings
Absolute maximum ratings are those values beyond which the device could be permanently damaged. Absolute maximum
ratings are stress ratings only and functional device operation is not implied.
Operating Conditions
Temperature Range
Parameter Min. Max. Units
V
CC
Shunt Regulator Current 55 mA
I
SENSE
Voltage -3 5 V
Voltage on Any Other Pin GND - 0.3 V
CCZ
+ 0.3 V
I
REF
20 mA
I
AC
Input Current 10 mA
Peak PFC OUT Current, Source or Sink 500 mA
Peak PWM OUT Current, Source or Sink 500 mA
PFC OUT, PWM OUT Energy Per Cycle 1.5 mJ
Junction Temperature 150 °C
Storage Temperature Range –65 150 °C
Lead Temperature (Soldering, 10 sec) 260 °C
Thermal Resistance (θ
JA
)
Plastic DIP 80 °C/W
Parameter Min. Max. Units
ML4841CP 0 70 °C
Electrical Characteristics
Unless otherwise specified, I
CC
= 25mA, R
T
= 23kΩ, R
RAMP1
= 28.7kΩ, C
T
= 400pF, C
RAMP1
= 270pF, T
A
=
Operating Temperature Range (Note 1)
Symbol Parameter Conditions Min. Typ. Max. Units
Voltage Error Amplifier
Input Voltage Range 0 7 V
Transconductance V
NON INV
= V
INV
, VEAO = 3.75V 40 70 100 µ
Feedback Reference Voltage 2.4 2.5 2.6 V
Input Bias Current Note 2 -0.5 -1.0 µA
Output High Voltage 6.0 6.7 V
Output Low Voltage 0.65 1.0 V
Source Current ∆V
IN
= ±0.5V, V
OUT
= 6V -40 -90 µA
Sink Current ∆V
IN
= ±0.5V, V
OUT
= 1.5V 40 90 µA
Open Loop Gain 60 75 dB
PSRR V
CCZ
- 3V < V
CC
< V
CCZ
- 0.5V 60 75 dB
Current Error Amplifier
Input Voltage Range -1.5 2 V
Transconductance V
NON INV
= V
INV
, VEAO = 3.75V 130 195 310 µ
Input Offset Voltage ±3 ±15 mV
Ω
Ω
P1-P3P4-P6P7-P9P10-P12P13-P15

ML4841CP

Mfr. #:
Buy ML4841CP
Manufacturer:
ON Semiconductor / Fairchild
Description:
Power Factor Correction - PFC PFC Controller PWM Combo
Lifecycle:
New from this manufacturer.
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